The present disclosure relates to an electronic component with a coil, a method for manufacturing the electronic component, and a power supply module. Specifically, the electronic component and the power supply module may have a coil component, such as an inductor element, surrounded by a metal composite magnetic material.
In the field of electronic components, it is well known to manufacture a coil component having a dust core (an air-coil core) by a press machine. According to this method, the press machine presses a mixture of magnetic powder and resin to seal a coil therewithin. This produces what is commonly referred to as a sealed coil-type magnetic component. Japanese Patent Publication Number JP 2007-81306 discloses a sealed coil-type magnetic component. The sealed coil-type magnetic component is configured with an air-core coil and a magnetic body. The magnetic body is made of a magnetic powder and resin mixture which seals the air-core coil. After the mixture is put in a metal mold of a press machine, the air-core coil is placed on the mixture. Thereafter, additional mixture is added over the air-core coil until the metal mold is filled. Next, upper and lower punches of the press machine press the mixture in the metal mold with a pressure of 3-5 ton/cm2.
Unfortunately, because the sealed coil-type magnetic component is formed under high pressure, the air-core coil may be deformed or broken. As such, the manufacturing yield decreases.
In the field of electronic components, it is also well known to manufacture a power supply module by injecting a thermoplastic resin. Such a power supply module is often configured with passive components such as a coil, a resistor and a capacitor, and an IC that are assembled on a circuit board. Japanese Utility Model Publication Number JPU H05-38994 discloses a method of manufacturing one such power supply module. According to the disclosed method, after an electronic component is assembled on a metal board, thermoplastic resin is injected on and around the electronic component. Then, the thermoplastic resin is hardened. However, because the magnetic permeability of the thermoplastic resin is quite low, an electromagnetic wave generated at the electric component (i.e., the coil) is transferred to other areas inside the power supply device but outside the power supply module. Therefore, electromagnetic interference may occur.